The Xbox Live Rewards loyalty scheme aims to reward players with
credits for actions like renewing their Xbox Live Gold membership,
playing games, buying content from the store, earning achievements
and generally being engaged members of the community.

As per the official site, with the change from MS Points to
local currency "it became necessary for us to evolve the way we
reward you. Instead of Microsoft Points, Xbox Live Rewards members
can now earn Rewards Credits, which are converted into your local
currency and deposited as cash directly into your Microsoft
account."

Eligibility for some rewards, particularly the VIP Rewards, will
be assessed at the beginning of each month and hinges on you having
an active Gold membership. Others involve tasks like completing
particular activity targets as designated by Punchcards or
providing data by filling out user surveys. Those with a high
Gamerscore should also be able to earn a rebate on purchases from
the Xbox Store.

"Once you rack up 5,000 credits or more, they'll be converted
into your local currency and deposited right into your Microsoft
account. Then it's off to the Xbox Stores, where you can spend your
money however you'd like!"

So you won't be able to take the money out of your Microsoft
wallet but if you're spending a fair amount of time (and cash) on
Xbox games or services chances are the credits will come in
handy.